Hurshid Tajibaev netted a hat-trick and Uzbekistan scored seven times in the second half to take pole position in Group C, but Petrov was still not satisfied.
"We are happy with the result but we are not happy with the team performance," he said.
"The first match is always very difficult and it’s pleasing to score 10 goals, but we’re not happy with the first half."
Tajibaev scored twice in the first period, with Nikolay Odushev also on target, while Malaysia’s Mohamad Zaidi Zul Khapri missed a penalty.
But Uzbekistan asserted their dominance in the second half with strikes from Tajibaev, Ilhmo Yusupdjanov (two), Umid Holmatov, Farruh Farhutdinov, Bahodir Ahmedov and Shuhrat Tojiboev.
Petrov, however, is adamant an improved display is required if Uzbekistan are to convert their tag of perennial challengers into title holders.
Tajibaev’s inspirational performance aside, Petrov believes his players must step up in order to go one better than the runners-up spot they secured in 2001 and 2006.
"Not all the players played well," added Petrov, whose side meet Korea Republic on Monday in their second game of the championship.
"Some of the players played a little bit lower than we expect.
"We hope if they can play at the same level we can be stronger."
Malaysia coach Poothathamby Balakrishnan was a dejected figure but was quick to praise Uzbekistan.
However, he attributed his side’s capitulation to numerous errors.
Malaysia struggled in both defence and attack and their misery was compounded when Mohamad Fuad Yusof was sent-off in the second half.
"We made a lot of mistakes," said P Balakrishnan.
The Malaysia coach was happy with the display in the opening quarter, but Uzbekistan scored three goals in the final eight minutes of the first half before the flood gates opened in the second period.
"Today my players for the first 12 minutes they were playing very well," he added.
"After that they became disorganised."
P Balakrishnan is aware his side must improve quickly ahead of Monday’s meeting with Lebanon, who are expected to duel for top spot in the pool with Uzbekistan.
"Tomorrow we have to get our game better to have any chance of going further in this championship," he said.